The invention is directed to the determination of a spatial position of an object.
The use of an autonomous robot system in industry is steadily increasing. The point of departure was the use of a robot system in fabrication. This robot system was thereby utilized in stationary fashion in order to implement repetitive but unchanging and permanently prescribed motion sequences. The demand for precision is thereby in the foreground. The disadvantage of this robot system is that it is bound to a location and, thus, has little flexibility.
T. Cord et al., Mobile autonome Roboter zum Transport von Containern, 11. Fachgesprxc3xa4ch, Karlsruhe, Eds. R. Dillmann, U. Rembold, T. Lxc3xcth, Springer Verlag, Berlin, Heidelberg, New York, pp. 1-9, 1995 discloses a mobile robot system that is no longer stationary but can move by itself. The navigation of the movement is thereby accomplished with specific preparations in the environment of the robot.
One example of this robot system is the driverless transport system that is used for transporting materials. This system is usually track-guided, i.e. it follows a fixed path. This concept has proven itself in practice but has the disadvantage that it is extremely inflexiblexe2x80x94see DE 35 369 74 A1. This is to be attributed thereto that the navigation control of the robot system ensues with a permanently present guide track Cord et al, supra. Before the transport robot is placed in operation, this is permanently introduced into the floor in the form of an electrical conductor along the travel path. An involved re-laying of the conductor is required given a change of the path guidance. The old conductor must be removed from the floor, the floor covering must be repaired, the new path guidance must be defined and the conductor must be placed into the floor along the new path. This denotes a great time expenditure and high costs.
R. Bauer, Integriertes hieracrhisches Navigationssystem fxc3xcr autonome mobile Roboter, pp. 17-23, pp. 35-41, Dissertation, Linz University, 1997 discloses an autonomous mobile robot system that is in the position of orienting itself, navigating and autonomously implementing a predetermined task in a dynamically changing environment completely independently without requiring a great expense for the preparation of the environment.
Various types of a position identification and navigation system have been developed thereforxe2x80x94Bauer. Such a system usually works on the basis of an imaging sensor. A sensor that detects the surroundings of the robot is thereby attached to the robot. Upon employment of a standard programmable computer, the sensor data are interpreted and a plot of the environment, similar to a map, is built up.
This map is interpreted in computer-supported fashion. Taking the kinematic and geometrical properties as well as the current position of the robot into consideration, the best possible navigation for a predetermined task is identifiedxe2x80x94DE 44 157 36 A1.
It is known from Bauer to employ an ultrasound sensor, a laser sensor or a stereo camera system as the sensor in a mobile robot.
The sensor system known from Bauer, however, exhibits a variety of disadvantages. Thus, the laser sensor or the stereo camera system is too expensive for the measurement use. In contrast thereto, the ultrasound sensor in fact has a low price and great ruggedness. However, the precision of such a sensor, its susceptibility to disturbance with respect to a temperature fluctuation, an external signal or a multiple reflection and the low range of the sensor make the use thereof only conditionally possible.
R. Bruchhaus, D. Pitzer, R. Primig, M. Schreiter, W. Wersing, N. Neumann, N. Hess, J. Vollheim, R. Kxc3x6hler, M. Simon, An 11xc3x976 Element Pyroelectric Detector Array Utilizing Self-Polarized PZT Thin Film Grown by Sputtering, Integrated Ferroelectrics, Vol. 17, pp. 369-376, 1997 also discloses that a pyroelectric material be employed for the development of a thermal sensor.
It is an object of the invention to determine the spatial position of an object in a flexible and cost-beneficial way.
According to the arrangement of the invention for determining a spatial position of the first object, an imaging thermal sensor is provided. A processing unit coupled to the sensor is provided with which a spatial position of the first object is identifiable from corresponding signals of the sensor with reference to at least one thermal marking that is acquired by the sensor. In a method of the invention for determining a spatial position of the first object with an imaging thermal sensor and a processing unit coupled to the sensor, with the sensor detecting a thermal image of the environment and outputting corresponding signals to the processing unit. With the processing unit, accepting the signals, evaluating the image in view of at least one thermal marking, and determining a spatial position of the first object dependent on the marking.
The arrangement for determining a spatial position of a first object comprises an imaging thermal sensor and a processing unit coupled to the sensor. The processing unit is configured such that the spatial position of the first object can be determined from corresponding signals of the sensor on the basis of at least one thermal marking that is acquired by the thermal sensor.
An object whose temperature differs from an ambient temperature is employed as thermal marking. The ambient temperature is the temperature in the environment of the first object.
In the method for determining a spatial position of a first object with an imaging thermal sensor and a processing unit coupled to the sensor, the following steps are implemented:
a) the sensor detects a thermal image of the environment and outputs corresponding signals to the processing unit;
b) the processing unit picks up the signals, evaluates the image in view of at least one thermal marking and determines the spatial position of the first object dependent on the marking.
The invention creates a very simple and cost-beneficial system for position determination since low costs are incurred both for the production of the imaging thermal sensor as well as for the creation of a thermal marking.
In particular, the possibility of being able to use a heat source that already exists, for instance a lighting member, or a thermal track that has arisen in a natural way, for instance a damp cleaning track, as the thermal marking make the invention attractive and practical.
In addition to these advantages, the employment of a thermal marking has the advantage that it is usually not visible for a person and is thus not disturbing.
The imaging thermal sensor is preferably a sensor with a pyroelectric thin-film. The sensor can thus be implemented as a very small and cost-beneficial component part.
It is provided in a further development that the arrangement comprises a unit that acts such on a second object such that the temperature of the second object differs from an ambient temperature and the second object can be recognized as the thermal marking. The advantage of this embodiment is comprised therein that a system that can be very flexibly utilized results due to the interaction of the first and second object.
The unit is preferably configured such that the second object is moistened with fluid, as a result whereof the temperature of the second object differs from the ambient temperature. And the second object can be recognized as the thermal marking. The advantage of this embodiment is comprised in the extremely simple and cost-beneficial way in which the thermal marking is produced.
Another advantageous development in view of the simplicity and compactness of the arrangement derives when the unit that acts on the subject object is the first object.
An especially simple structure of the arrangement derives when the imaging thermal sensor is attached to the first object.
The arrangement is preferably utilized such that the first object is a robot. In this way, there is a very simple, flexible and economical system for position determination for the robot.